Using an EPROM as a UV detector. I was planning to make a UV meter using an EPROM. The idea was that ultraviolet light erases an EPROM. When a fully programmed EPROM (all zero's) is exposed to uv light I should clearly see the number of bits (one's) increasing. So I have built a small device that counts the number of bits (one's) in an EPROM. I had guessed that the speed of increase of bits would certainly be a measure of the UV intensity. But... When exposing the EPROM to uv-light I expected a smooth and stable increase of bits, but that didn't happen. In stead, after some time of exposure to uv-light the bitcount begins to vary very much and it seems that the bits (all Floating Gate devices) become unstable. Knowing that the bits become unstable, I covered the EPROM window with aluminium and watched what would happen. Not to my surprise the bitcount kept varying (I measure 64k bit 4 times per second). I have a built in threshold of 50 counts, and everytime 2 measurements have a difference of 50 of more I show a flash on a LED. And it is flasing very randomly between 20 to 60 flashes per minute. Now my question is: What is it exactly what I measure? I don't know much about uv or radiation, so perhaps you can help me out???